Reliable and efficient compression systems have been developed and are used in a myriad of industrial processes (e.g., petroleum refineries, offshore oil production platforms, and subsea process control systems). There is, however, an ever-increasing demand for smaller, lighter, and more compact compression systems. Accordingly, compact motor-compressors that incorporate compressors directly coupled to high-speed electric motors have been developed. Conventional compact motor-compressors may combine a high-speed electric motor with a compressor, such as a centrifugal compressor, in a single, hermetically sealed housing. In compact motor-compressors, the high-speed electric motor may operate in a process fluid contained in the housing, which may be maintained at a pressure from about 1 megapascal (MPa) to about 30 MPa. To deliver an electrical current across the pressure boundary of the housing and power the high-speed electric motor, high voltage penetrators (HVPs) are often utilized. In topside or terrestrial (e.g., ground based) environments with ambient air external conditions, the HVPs may be contained in a pipe section extending from the sealed housing. These pipe sections, however, are neither practical nor adequate for the larger and more complex HVPs required in subsea environments.
In view of the foregoing, compact motor-compressors used in subsea environments may often include a terminal assembly in lieu of the pipe section to engage or couple with the HVPs. FIG. 1 illustrates a partial, cross-sectional view of a conventional compact motor-compressor 100 including a conventional terminal assembly 102. The motor-compressor 100 may combine a pressurized, high-speed motor 120 with a compressor 130 in a hermetically sealed housing 112. The motor-compressor 100 may further include a terminal assembly 102 disposed about the housing 112 and configured to couple with one or more HVPs 106, 108, 110. The HVPs 106, 108, 110 may be configured to receive an electrical current from a sea- or land-based power source and deliver the electrical current to the motor 120 via the terminal assembly 102. To limit power losses resulting from induced eddy currents, the terminal assembly 102 may be cast with costly non-magnetic metals. However, in conventional motor-compressors 100, the terminal assembly 102 may often be cast integral with the housing 112, thereby hindering the ability to fabricate the terminal assembly 102 and the housing 112 from different materials. As such, the housing 112 and the terminal assembly 102 are often cast with the same cost effective metallic materials and the resulting power losses from induced eddy currents are accepted. Further, in conventional motor-compressors 100, the HVPs 106, 108, 110 are often coupled with the terminal assembly 102 in a co-linear orientation, which results in an increased distance and an increased amount of metallic material interposed between each of the HVPs 106, 108, 110. The increased amount of metallic material may also contribute to the overall power losses from induced eddy currents.
What is needed, then, is an improved, cost-effective motor-compressor system and method of operating thereof, including a terminal assembly capable of minimizing induced power losses.